Bonding of a fluoropolymer layer to a substrate

ABSTRACT

The present invention comprises a substrate having a fluoropolymer on at least one of its surfaces wherein one of the substrates or the fluoropolymer comprises a hydride function MH wherein M is Si, Ge, Sn or Pb. The invention further comprises articles comprising the substrate and fluoropolymer; a method of bonding the fluoropolymer to the substrate; a fluoropolymer composition that contains the fluoropolymer, a polyhydroxy cure composition, and an organic composition comprising the hydride function MH; a premix that contains the fluoropolymer and the hydride function MH; and a fluoropolymer composition that comprises (a) a thermoplastic fluoropolymer comprising Cl, Brand/or I atoms and (b) an organic compound that comprises the hydride function MH.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Ser. No. 10/282,677, filed Oct.29, 2002, now allowed, which claims priority to Provisional ApplicationNo. 60/336,405, filed Oct. 31, 2001, the disclosures of which are hereinincorporated by reference.

FIELD

The present invention relates to an improvement in bonding of afluoropolymer, i.e. a polymer having a fluorinated backbone, to asubstrate such as for example a non-fluorinated elastomer, siliconeelastomer or even another fluoropolymer such as for example a layer of athermoplastic fluoropolymer. In particular, the present inventionrelates to the use of an organic compound having a hydride function MH,wherein M is selected from Si, Ge, Sn and Pb to improve the bondingproperties of a fluoropolymer.

BACKGROUND

The beneficial properties of fluoropolymers are well known in the artand include for example, high temperature resistance, high chemicalresistance including for example high resistance to solvents, fuels andcorrosive chemicals, and non-flammability. Because of these beneficialproperties, fluoropolymers find wide application particularly wherematerials are exposed to high temperature and/or chemicals.

For example, fluoropolymers are used in fuel management systems whichinclude for example fuel tanks, fuel filler lines and fuel supply linesin cars or other motor vehicles because of their excellent resistance tofuels and because of the good barrier properties that can be achievedwith fluoropolymers. Additionally, fluoropolymers, in particularfluoroelastomers, may be used in a hose connecting the compressor of aturbo engine with an intercooler. Because of the high temperature of thecompressed air, non-fluorine elastomers such as ethylene acrylic basedelastomers or silicone elastomers cannot be used for such a hose.

Fluoropolymers are generally more expensive than non-fluorine polymersand accordingly, materials have been developed in which thefluoropolymer is used in combination with other materials to reduce theoverall cost of an article. For example, in the aforementioned hose usedin turbo engines, it has been proposed to use a relatively thin layer offluoroelastomer as an inner layer of a multilayer hose where theouterlayer of the hose is then a non-fluorine elastomer such as forexample a silicone elastomer. It is required in such a multilayer hosethat the fluoropolymer layer be firmly and reliably bonded to the otherlayers of the hose. Unfortunately, bonding of fluoropolymers to othersubstrates is often difficult and in particular bonding to siliconeelastomers has been found difficult. This is further complicated by thefact that various silicone compositions exist such that in one instancea particular fluoropolymer composition may show good bonding, yet inanother instance satisfactory bonding may not be obtained. To solve thisproblem, tie layers have been proposed between the fluoropolymer andother materials such as a silicone elastomer, but this increases costand makes the manufacturing more complicated.

A further application in which a multi-layer article including afluoropolymer layer is used is in a fuser member of a plain papercopier. Such a fuser member typically has a thermally conductivesilicone elastomer which is bonded to a fluoroelastomer surface layerwhich may also include conductive particles. Such a fuser member isdisclosed in for example U.S. Pat. No. 5,217,837. This U.S. patentdescribes a multilayer fuser member in which the silicone elastomer isbonded to the fluoroelastomer with the intermediate of an adhesivelayer. The manufacturing of such a fuser member is unfortunatelycumbersome. A similar system is described in U.S. Pat. No. 6,020,038.

Further, in certain applications, it may further be desirable to bondfluoropolymers of different nature and composition to each other. Forexample, in a fuel supply line, it may be desirable to bond afluoroelastomer layer to fluorothermoplastic polymer layer. Althoughboth polymers are fluoropolymers, desired bond strength may still not beachieved.

Accordingly, it would be desirable to find a way of improving bonding ofa fluoropolymer to other substrates such as for example non-fluorineelastomers, silicone rubbers and other fluoropolymers. Preferably, thissolution is cost effective, convenient and reliable and can be appliedto a wide variety of substrates.

SUMMARY

In one embodiment, the present invention provides a material comprisinga substrate having on at least one surface thereof a fluoropolymer layercomprising a fluoropolymer. The fluoropolymer layer and/or the substratecomprises an organic compound comprising a hydride function MH, whereinM is selected from Si, Ge, Sn and Pb. This material can be formed intoan article in which the fluoropolymer is firmly bonded to the substrateby reacting the fluoropolymer layer to the substrate. Accordingly, theinvention further provides the article that is obtained from reactingthe fluoropolymer layer to the substrate.

In a further aspect, the present invention provides a method of bondinga fluoropolymer to a substrate comprising reacting the fluoropolymerlayer to the substrate in the presence of an organic compound having ahydride group comprising a hydride function MH, wherein M is selectedfrom Si, Ge, Sn and Pb.

It has been found in connection with the present invention that afluoropolymer layer can be effectively bonded to a substrate if anorganic compound having a hydride function MH is present. In particular,good bonding of a fluoroelastomer layer to other elastomers, includingnon-fluorine type elastomers such as silicone rubbers can be obtained.Surprisingly, these good bonding properties can be obtained with a widevariety of silicone rubber compositions.

In a further aspect, the present invention relates to a particularfluoropolymer composition that can be used for bonding a fluoroelastomerlayer to a substrate. This aspect of the invention provides afluoropolymer composition that comprises:

-   -   (a) a fluoropolymer;    -   (b) a cure composition comprising a polyhydroxy compound; and    -   (c) an organic compound comprising a hydride function MH,        wherein M is selected from Si, Ge, Sn and Pb.

In yet a still further aspect, the present invention provides a premixfor providing a curable fluoropolymer composition, said premixcomprising a fluoropolymer and an organic compound comprising a hydridefunction MH, wherein M is selected from Si, Ge, Sn and Pb, and saidcurable fluoropolymer composition being obtainable from said premix byadding thereto one or more components of a cure composition.

In a further aspect, a fluoropolymer composition is provided thatcomprises:

-   -   (a) a thermoplastic fluoropolymer comprising chlorine, bromine        and/or iodine atoms; and    -   (b) an organic compound comprising a hydride function MH,        wherein M is selected from Si, Ge, Sn and Pb.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures are included by way of further illustration ofsome embodiments of the present invention. It will be understood thatthese drawings merely serve to illustrate the invention without limitingthe invention in any way thereto.

FIGS. 1 and 2 are cross-sectional schematic representations of amulti-layer hose or tube that can be obtained with the invention.

DETAILED DESCRIPTION

The organic compound having one or more hydride functions MH may eitherbe a simple organic compound or a polymeric compound. By “polymericcompound” is meant that the compound comprises repeating units that areactually or conceptually derived from lower molecular weight compounds,i.e. monomers. The polymerization degree may vary widely and includes alow polymerization degree such as for example a polymerization degree of2 to 50 repeating units as well as a large polymerization degree of morethan 50. Thus, the term “polymeric compound” should be understood toinclude oligomeric compounds that typically have a low polymerizationdegree. If the organic compound is polymeric, the hydride function maybe contained in the terminating group of the polymeric chain and/or in arepeating unit of the polymeric compound.

The organic compound having one or more MH functions is typically anon-fluorinated compound although the possibility of using an organiccompound that has fluorine substituents is not excluded.

In one embodiment of the present invention, the organic compound is asiloxane or a silazane that comprises one or more MH functions.Typically, when the organic compound is a siloxane or a silazane, the MHfunctions will be —SiH functions. Preferably, the SiH function will bean —OSiH or a —NSiH whereby the hydrogen is attached to a silicon atomthat is further bonded to an oxygen or nitrogen atom. The siloxane orsilazane may be a simple low molecular weight organic compound or may bea polymeric compound including for example a polysiloxane which may belinear, branched or cyclic.

Examples of low molecular weight siloxanes include for example alkoxysilanes corresponding to the formula:(R^(a))_(a)(R^(b)O)_(t)SiH_(w)  (I)wherein each R^(a) independently represents an alkyl group such as forexample methyl or ethyl or another lower alkyl (C₁-C₇ alkyl group) or analkyl group substituted with a substituent such as for example an arylgroup, an ester, an alkoxy etc., or aryl group optionally substitutedsuch as for example with an alkyl group, an ester, an alkoxy etc.; eachR^(b) independently represents an alkyl group, preferably a lower alkylgroup and which may optionally be substituted; t and w represent aninteger of at least 1 and the sum of s+t+w being 4. Examples ofsiloxanes according to the above formula include HSi(OCH₂CH₃)₃ and(CH₃)₂(CH₃CH₂O)SiH.

In accordance with another embodiment of the present invention, theorganic compound is a polysiloxane (oligomer or polymer), comprising apolysiloxy backbone. Such polymer or oligomer may be terminated by agroup containing one or more SiH functions and/or may contain SiH groupsdistributed along the backbone. The SiH groups may form part of thebackbone or they can be present in a side group attached to thebackbone.

For example, the polysiloxanes for use with this invention include thosethat correspond to the formula:

wherein R¹, R², R³, R⁶, R⁷, R⁸ and R⁹ each independently representshydrogen, an alkoxy group, an alkyl optionally substituted such as forexample with an aryl group, an ester, an alkoxy etc., or aryl groupoptionally substituted such as for example with an alkyl group, anester, an alkoxy etc.; R⁴ and R⁵ each independently represents an alkoxygroup, an alkyl or aryl group each of which may optionally besubstituted, x represents a value of 0 to 150, y represents a value of 0to 150 and with the proviso that when x=0, at least one of R¹, R², R⁶,R⁷, R⁸ and R⁹ represents a hydrogen atom.

Specific examples of siloxanes include 1,1,3,3 tetraisopropyldisiloxane, diphenyl-1,1,3,3-tetrakis(dimethylsiloxy)disiloxaneavailable from United Chem, silylhydride terminatedpoly(dimethylsiloxane), poly(methyl hydro siloxane) and copolymers ofdimethylsiloxane and methylhydrosiloxane.

Further siloxanes that can be used may be cyclic such as thosecorresponding to the formula:

wherein R^(c) represents hydrogen, an alkyl group or an aryl group,R^(d) and R^(e) each independently represents an alkyl or aryl group, iis at least 1 and the sum of i+j is at least 3. Specific examples ofcyclic siloxanes according to the above formula are 1,3,5-trimethylcyclosiloxane and 1-phenyl-3,3,5,5-tetramethyl cyclosiloxane.

Polysiloxanes and siloxanes having SiH groups are known in the art andcan be produced according to well-known procedures such as disclosed infor example: Encyclopedia of Polymer Science and Engineering, SecondEdition, V15, Silicones, pgs. 204-308, John Wiley & Sons, 1989.Siloxanes having SiH groups are also generally commercially available.Preferably, the siloxane or polysiloxane will have a molecular weightbetween 150 g/mol and 10,00 g/mol.

Suitable silazanes for use with the invention include for exampledisilazanes corresponding to the formula:H_(u)Si(R^(f))_(3-u)—NR^(g)—SiH_(u)(R^(h))_(3-u)  (IV)wherein u is 1 or 2, R^(f) and R^(h) each independently represents analkyl group or an aryl group and R^(g) represents hydrogen, an alkylgroup or an aryl group. A specific example of a silazane isHSi(CH₃)₂—NH—(CH₃)₂H.

In a further embodiment of the present invention, the organic compoundcorresponds to the formula:

wherein R represents a hydrocarbon group optionally comprising one ormore substituents and wherein the R groups may be the same or differentand whereby two R groups may be linked to each other so as to form aring, M is selected from Si, Ge, Sn and Pb, q is a value of 1 to 3, x isa value of 1 to 3, y and z represent a value of 0 to 3 and the sum ofy+z=4-x. Examples of substituents that may be present on the hydrocarbongroup R include alkoxy, aryloxy, halogens such as chlorine and bromine,nitrile groups, hydroxy groups and amino groups. The backbone of thehydrocarbon group may further be interrupted by one or more heteroatomssuch as for example oxygen and nitrogen atoms. Typical examples ofhydrocarbon groups include saturated or unsaturated linear, branched orcyclic aliphatic groups and aromatic groups. Specific examples are C₁-C₅alkyl groups, aryl groups having 6 to 12 carbon atoms, arylalkyl andalkylaryl groups having 7 to 14 carbon atoms.

Compounds according to formula (V) include in particular those accordingto formula (VI):R_(y)Si—H_(x)  (VI)wherein R, y and x have the same meaning as above. Preferably, R in theabove formula (VI) is an aryl group such as for example phenyl.

Compounds of formula (V) and (VI) are known and have been described infor example J. Am. Chem. Soc., 116 (1994), page 4521-4522. Examples ofcompounds according to formula V include tri(n-butyl)tin hydride,tri(ethyl)silyl hydride, di(trimethylsilyl)silylmethyl hydride,tri(trimethylsilyl)silyl hydride, tri(phenyl)silyl hydride. Compounds offormula (V) have further been disclosed in EP 761 735.

The organic compound is typically included in a composition forproviding the fluoropolymer layer. However, this may not be necessaryand it is also contemplated that the organic compound is included in thesubstrate to which the fluoropolymer is to be bonded in particular inthe surface layer of the substrate to which the fluoropolymer is beingbonded. The amount of organic compound used in a composition forproviding the fluoropolymer layer may vary widely and the optimal amountcan be readily determined by one skilled in the art through routineexperimentation. Typically, an amount of 0.01% by weight to 5% byweight, preferably between 0.1% by weight and 4% by weight based on theweight of fluoropolymer is included in the composition for preparing thefluoropolymer layer.

The fluoropolymer of the fluoropolymer layer may have a partially orfully fluorinated backbone. Particularly preferred fluoropolymers arethose that have a backbone that is at least 30% by weight fluorinated,preferably at least 50% by weight fluorinated, more preferably at least65% by weight fluorinated.

Examples of fluoropolymers for use in this invention include polymers ofone or more fluorinated monomers optionally in combination with one ormore non-fluorinated monomers. Examples of fluorinated monomers includefluorinated C₂-C₈ olefins that may have hydrogen and/or chlorine atomssuch as tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE),2-chloropentafluoropropene, dichlorodifluoroethylene, vinyl fluoride,vinylidene fluoride (VDF) and fluorinated alkyl vinyl monomers such ashexafluoropropylene (HFP); fluorinated vinyl ethers, includingperfluorinated vinyl ethers (PVE) and fluorinated allyl ethers includingperfluorinated allyl ethers. Suitable non-fluorinated comonomers includevinyl chloride, vinylidene chloride and C₂-C₈ olefins such as ethylene(E) and propylene (P).

Examples of perfluorovinyl ethers that can be used in the inventioninclude those that correspond to the formula:CF₂═CF—O—R_(f)wherein R_(f) represents a perfluorinated aliphatic group that maycontain one or more oxygen atoms.

Particularly preferred perfluorinated vinyl ethers correspond to theformula:CF₂═CFO(R^(a) _(f)O)_(n)(R^(b) _(f)O)_(m)R^(c) _(f)wherein R^(a) _(f) and R^(b) _(f) are different linear or branchedperfluoroalkylene groups of 1-6 carbon atoms, in particular 2 to 6carbon atoms, m and n are independently 0-10 and R^(c) _(f) is aperfluoroalkyl group of 1-6 carbon atoms. Specific examples ofperfluorinated vinyl ethers include perfluoro (methyl vinyl) ether(PMVE), perfluoro (ethyl vinyl) ether (PEVE), perfluoro (n-propyl vinyl)ether (PPVE-1), perfluoro-2-propoxypropylvinyl ether (PPVE-2),perfluoro-3-methoxy-n-propylvinyl ether, perfluoro-2-methoxy-ethylvinylether and CF₃—(CF₂)₂—O—CF(CF₃)—CF₂—O—CF(CF₃)—CF₂—O—CF═CF₂.

Suitable perfluoroalkyl vinyl monomers correspond to the generalformula:CF₂═CF—R^(d) _(f) or CH₂═CH—R^(d) _(f)wherein R_(d) ^(f) represents a perfluoroalkyl group of 1 to 10,preferably 1 to 5 carbon atoms. A typical example of a perfluoroalkylvinyl monomer is hexafluoropropylene.

The fluoropolymers for use in connection with the present invention canbe made in accordance with any of the known polymerization methods formaking fluoropolymers. Such methods include without limitation, aqueousemulsion polymerization, suspension polymerization and polymerization inan organic solvent.

According to a particular embodiment, the fluoropolymer is asubstantially amorphous polymer that shows hardly any melting point ifat all. Such fluoropolymers are particularly suitable for providingfluoroelastomers, which are typically obtained upon curing of anamorphous fluoropolymer. Amorphous fluoropolymers include for examplecopolymers of vinylidene fluoride and at least one terminallyethylenically-unsaturated fluoromonomer containing at least one fluorineatom substituent on each double-bonded carbon atom, each carbon atom ofsaid fluoromonomer being substituted only with fluorine and optionallywith chlorine, hydrogen, a lower fluoroalkyl radical, or a lowerfluoroalkoxy radical. Specific examples of copolymers include forexample copolymers having a combination of monomers as follows: VDF-HFP,TFE-P, VDF-TFE-HFP, VDF-TFE-PVE, TFE-PVE, E-TFE-PVE and any of theaforementioned copolymers further including units derived from achlorine containing monomer such as CTFE. Still further examples ofsuitable amorphous copolymers include copolymers having a combination ofmonomers as in CTFE-P.

Preferred amorphous fluoropolymers generally comprise from 20 to 85%,preferably 50 to 80% by moles of repeating units derived from VDF, TFEand/or CTFE, copolymerized with one or more other fluorinatedethylenically unsaturated monomer and/or one or more non fluorinatedC₂-C₈ olefins, such as ethylene and propylene. The units derived fromthe fluorinated ethylenically unsaturated comonomer when present isgenerally between 5 and 45 mole %, preferably between 10 and 35 mole %.The amount of non-fluorinated comonomer when present is generallybetween 0 and 50 mole %, preferably between 1 and 30 mole %.

In an embodiment where a fluoroelastomer is desired, the fluoropolymerwill typically be cured. The fluoropolymer layer may be cured by any ofthe methods known to those skilled in the art and will typically includea cure composition such that the fluoropolymer layer can be cured. Thecure composition typically includes one or more components that causethe fluoropolymer chains to link with each other thereby forming a threedimensional network. Such components may include catalysts, curingagents and/or coagents.

In one embodiment of curing the fluoropolymer layer a so called peroxidecure system may be used. In a typical peroxide cure system, thefluoropolymer is provided with one or more cure sites that comprise ahalogen capable of participating in a peroxide cure reaction and thecomposition for providing the fluoropolymer contains an organicperoxide. The halogen capable of participating in a peroxide curereaction is typically bromine or iodine and may be distributed along thepolymer chain and/or may be contained in the end groups of thefluoropolymer. Typically, the amount of bromine or iodine contained inthe fluoropolymer is between 0.001 and 5%, preferably between 0.01 and2.5%, by weight with respect to the total weight of the fluoropolymer.It has further been found that chlorine is also capable of participatingin a peroxide cure reaction of the fluoropolymer if the organic compoundhaving MH functions is present. Accordingly, fluoropolymers that alsocontain chlorine atoms and/or bromine or iodine can be used for curingin a peroxide cure reaction. The amount of chlorine in the fluoropolymermay vary from 0.001% by weight to 10% by weight but is typically between0.01% by weight and 5% by weight based on the weight of fluoropolymer. Aparticularly suitable polymer for use with a peroxide cure system is apolymer that includes units that are derived from CTFE or anotherchlorine containing monomer. Specific examples include copolymers thathave a combination of CTFE-VDF-TFE-HFP as monomers. Of course a chlorinecontaining fluoropolymer for use in a peroxide cure system mayadditionally be modified with bromine and/or iodine. The fluoropolymerfor use in the peroxide cure reaction typically will have a molecularweight of 10⁴ to 5×10⁵ g/mol and the molecular weight distribution canbe monomodal as well as bimodal or multimodal.

In order to introduce halogens, which are capable of participation inthe peroxide cure reaction, along the chain, the copolymerization of thebasic monomers of the fluoropolymer is carried out with a suitablefluorinated cure-site monomer (see for instance U.S. Pat. Nos.4,745,165, 4,831,085, and 4,214,060). Such comonomer can be selected forinstance from:

-   -   (a) bromo- or iodo-(per)fluoroalkyl-perfluorovinylethers having        the formula:        Z—R_(f)—O—CF═CF₂        wherein Z is Br or I, Rf is a (per)fluoroalkylene C₁-C₁₂,        optionally containing chlorine and/or ether oxygen atoms; for        example: BrCF₂—O—CF═CF₂, BrCF₂CF₂—O—CF═CF₂,        BrCF₂CF₂CF₂—O—CF═CF₂, CF₃CFBrCF₂—O—CF═CF₂, and the like;    -   (b) bromo- or iodo (per)fluoroolefins such as those having the        formula:        Z′—R′_(f)—CF═CF₂        wherein Z′ is Br or I, R′_(f) is a (per)fluoroalkylene C₁-C₁₂,        optionally containing chlorine atoms; for instance:        bromotrifluoroethylene, 4-bromo-perfluorobutene-1, and the like;        or bromofluoroolefins such as 1-bromo-2,2-difluoroethylene and        4-bromo-3,3,4,4-tetrafluorobutene-1;    -   (c) non-fluorinated bromo-olefins such as vinyl bromide and        4-brorno-1-butene;    -   (d) chlorine containing monomers including chlorine containing        fluorinated monomers such as for example chlorine containing        fluorinated C₂-C₈ olefins such as CTFE and non-fluorinated        chlorine containing monomers such as chlorinated C₂-C₈ olefins        such as vinyl chloride and vinylidene chloride.

In replacement of or in addition to the cure site comonomer, thefluoropolymer can contain a cure site component in terminal position,deriving from a suitable chain transfer agent introduced in the reactionmedium during the polymer preparation, as described in U.S. Pat. No.4,501,869 or derived from a suitable initiator. Examples of usefulinitiators include X(CF₂)_(n)SO₂Na with n=1 to 10 (where X is Br or I)or an initiator composition comprising ammonium persulfate and potassiumbromide.

Examples of chain transfer agents include those having the formulaR_(f)Br_(x), wherein R_(f) is a x-valent (per)fluoroalkyl radicalC₁-C₁₂, optionally containing chlorine atoms, while x is 1 or 2.Examples include CF₂Br₂, Br(CF₂)₂Br, Br(CF₂)₄Br, CF₂ClBr, CF₃CFBrCF₂Br,and the like. Further examples of suitable chain transfer agents aredisclosed in U.S. Pat. No. 4,000,356.

Suitable organic peroxides are those which generate free radicals atcuring temperatures. A dialkyl peroxide or a bis(dialkyl peroxide) whichdecomposes at a temperature above 50° C. is especially preferred. Inmany cases it is preferred to use a di-tertiarybutyl peroxide having atertiary carbon atom attached to peroxy oxygen. Among the most usefulperoxides of this type are2,5-dimethyl-2,5-di(tertiarybutylperoxy)hexyne-3 and2,5-dimethyl-2,5-di(tertiarybutylperoxy)hexane. Other peroxides can beselected from such compounds as dicumyl peroxide, dibenzoyl peroxide,tertiarybutyl perbenzoate, α,α′-bis(t-butylperoxy-diisopropylbenzene),and di[1,3-dimethyl-3-(t-butylperoxy)-butyl]carbonate. Generally, about1-3 parts of peroxide per 100 parts of fluoropolymer is used.

Another component which is usually included in a cure composition basedon an organic peroxide, is a coagent composed of a polyunsaturatedcompound which is capable of cooperating with the peroxide to provide auseful cure. These coagents can be added in an amount equal to 0.1 and10 parts per hundred parts fluoropolymer, preferably between 2 to 5parts per hundred parts fluoropolymer. Examples of useful coagentsinclude triallyl cyanurate; triallyl isocyanurate; triallyltrimellitate; tri(methylallyl) isocyanurate;tris(diallylamine)-s-triazine; triallyl phosphite; N,N-diallylacrylamide; hexaallyl phosphoramide; N,N,N′,N′-tetraalkyltetraphthalamide; N,N,N′,N′-tetraallyl malonamide; trivinylisocyanurate; 2,4,6-trivinyl methyltrisiloxane;N,N′-m-phenylenebismaleimide; diallyl-phthalate andtri(5-norbornene-2-methylene)cyanurate. Particularly useful is triallylisocyanurate. Other useful coagents include the bis-olefins disclosed inEPA 0 661 304 A1, EPA 0 784 064 A1 and EPA 0 769 521 A1.

According to a further embodiment, the curing of the fluoropolymer maybe effected using a polyhydroxy compound and the cure composition willthus comprise a polyhydroxy compound. The advantage of using apolyhydroxy compound for curing the fluoropolymer is that it will not benecessary to include special cure site components in the fluoropolymer.In addition to the polyhydroxy compound, a polyhydroxy curing systemgenerally also comprises one or more organo-onium accelerators inaddition to the polyhydroxy compound. The organo-onium compounds usefulin the present invention typically contain at least one heteroatom,i.e., a non-carbon atom such as N, P, S, O, bonded to organic orinorganic moieties and include for example ammonium salts, phosphoniumsalts and iminium salts. One class of quaternary organo-onium compoundsuseful in the present invention broadly comprises relatively positiveand relatively negative ions wherein a phosphorus, arsenic, antimony ornitrogen generally comprises the central atom of the positive ion, andthe negative ion may be an organic or inorganic anion (e.g., halide,sulfate, acetate, phosphate, phosphonate, hydroxide, alkoxide,phenoxide, bisphenoxide, etc.).

Many of the organo-onium compounds useful in this invention aredescribed and known in the art. See, for example, U.S. Pat. No.4,233,421 (Worm), U.S. Pat. No. 4,912,171 (Grootaert et al.), U.S. Pat.No. 5,086,123 (Guenthner et al.), and U.S. Pat. No. 5,262,490 (Kolb etal.), U.S. Pat. No. 5,929,169, all of whose descriptions are hereinincorporated by reference. Representative examples include the followingindividually listed compounds and mixtures thereof:

-   -   triphenylbenzyl phosphonium chloride    -   tributylallyl phosphonium chloride    -   tributylbenzyl ammonium chloride    -   tetrabutyl ammonium bromide    -   triaryl sulfonium chloride    -   8-benzyl-1,8-diazabicyclo [5,4,0]-7-undecenium chloride    -   benzyl tris(dimethylamino) phosphonium chloride    -   benzyl(diethylamino)diphenylphosphonium chloride        Another class of useful organo-onium compounds include those        having one or more pendent fluorinated alkyl groups. Generally,        the most useful fluorinated onium compounds are disclosed by        Coggio et al. in U.S. Pat. No. 5,591,804.

The polyhydroxy compound may be used in its free or non-salt form or asthe anionic portion of a chosen organo-onium accelerator. Thecrosslinking agent may be any of those polyhydroxy compounds known inthe art to function as a crosslinking agent or co-curative forfluoroelastomers, such as those polyhydroxy compounds disclosed in U.S.Pat. No. 3,876,654 (Pattison), and U.S. Pat. No. 4,233,421 (Worm).Representative aromatic polyhydroxy compounds include any one of thefollowing: di-, tri-, and tetrahydroxybenzenes, naphthalenes, andanthracenes, and bisphenols of the following formula:

wherein A is a difunctional aliphatic, cycloaliphatic, or aromaticradical of 1 to 13 carbon atoms, or a thio, oxy, carbonyl, sulfonyl, orsulfonyl radical, A is optionally substituted with at least one chlorineor fluorine atom, x is 0 or 1, n is 1 or 2, and any aromatic ring of thepolyhydroxy compound is optionally substituted with at least one atom ofchlorine, fluorine, bromine, or with a carboxyl or an acyl radical(e.g., —COR where R is H or a C1 to C8 alkyl, aryl, or cycloalkyl group)or alkyl radical with, for example, 1 to 8 carbon atoms. It will beunderstood from the above bisphenol formula that the—OH groups can beattached in any position (other than number one) in either ring. Blendsof two or more of these compounds are also used.

One of the most useful and commonly employed aromatic polyphenols of theabove formula is 4,4′-hexafluoroisopropylidenyl bisphenol, known morecommonly as bisphenol AF. The compounds 4,4′-dihydroxydiphenyl sulfone(also known as Bisphenol S) and 4,4′-isopropylidenyl bisphenol (alsoknown as bisphenol A) are also widely used in practice.

The cure composition based on polyhydroxy compounds may further includean acid acceptor. Acid acceptors can be inorganic or blends of inorganicand organic. Examples of inorganic acceptors include magnesium oxide,lead oxide, calcium oxide, calcium hydroxide, dibasic lead phosphite,zinc oxide, barium carbonate, strontium hydroxide, calcium carbonate,etc. Organic acceptors include epoxies, sodium stearate, and magnesiumoxalate. The preferred acid acceptors are magnesium oxide and calciumhydroxide. The acid acceptors can be used singly or in combination, andpreferably are used in amounts ranging from about 2 to 25 parts per 100parts by weight of the fluoropolymer.

In a further embodiment of the invention, the cure composition maycomprise an organic peroxide and a polyhydroxy based cure system asdescribed above. Such cure composition can be used with a fluoropolymerthat has a halogen capable of participating in a peroxide cure reactionas well as with fluoropolymers that do not contain such halogens. If thefluoropolymer has halogens capable of participating in the peroxide curereaction, a cure composition having a polyhydroxy compound and aperoxide can provide for a so called dual cure. The use of an organicperoxide in the cure composition is particularly beneficial if thefluoropolymer is to form a fluoroelastomer layer bonded to anotherelastomer that is also formed with the use of a peroxide cure systemsuch as for example in case of a silicone based elastomer.

The fluoropolymer composition for providing the fluoropolymer layer maycontain further additives, such as carbon black, stabilizers,plasticizers, lubricants, fillers, and processing aids typicallyutilized in fluoropolymer compounding can be incorporated into thecompositions of the present invention, provided they have adequatestability for the intended service conditions.

The fluoropolymer compositions may be prepared by mixing afluoropolymer, a cure composition and the organic compound havinghydride function(s) and other additives in conventional rubberprocessing equipment. Such equipment includes rubber mills, internalmixers, such as Banbury mixers, and mixing extruders.

It is further possible to prepare a premix of the fluoropolymercomposition whereby the premix comprises the fluoropolymer and part ofother components of the full composition but not all of them. Thecomposition of such a premix will depend on desired stability of thepremix over a desired period of storage. For example, the premix maycomprise the fluoropolymer, the organic compound having hydride groupsMH and one or more components of a cure composition but not all of thecomponents necessary to obtain a curable composition. For example, incase the cure composition comprises peroxide, it will generally bedesired to exclude the peroxide from the premix and only add theperoxide at the time of preparing the fluoropolymer composition forpreparing the fluoropolymer layer.

In a further embodiment of the present invention, the fluoropolymerlayer may comprise a thermoplastic fluoropolymer, in particular a meltprocessible thermoplastic fluoropolymer. By the term “thermoplasticfluoropolymer” is meant a fluoropolymer that is at least partiallycrystalline such that a distinct melting point, typically 100° C. ormore, can be identified for example through a DSC scan of the polymer.By the term “melt processible” is meant that the fluoropolymer has amelt viscosity such that it can be processed from the melt throughtypical melt extrusion equipment that is available. In a particularpreferred embodiment of the present invention, the thermoplasticfluoropolymer is a chlorine containing fluoropolymer. Such chlorineatoms may be introduced in the fluoropolymer through copolymerizationwith chlorine containing fluorinated monomers or via chain transferagents and/or initiator systems as described above. Alternatively oradditionally, the thermoplastic fluoropolymer may contain bromine and/oriodine atoms which can also be introduced by copolymerization of abromine or iodine containing comonomer, e.g. as listed above, or throughthe use of chain transfer agents and/or initiator systems that introduceBr or I atoms. Specific examples of thermoplastic fluoropolymers thatmay be used with this invention are copolymers having the followingcombination of monomers: CTFE-VDF; CTFE-TFE, CTFE-TFE-HFP,CTFE-TFE-HFP-VDF; CTFE-TFE-HFP-VDF-PPVE, CTFE-TFE-E; bromine or chlorinecontaining E-TFE copolymers and bromine or chlorine containingTFE-HFP-VDF copolymers.

In accordance with the method of the present invention for bonding afluoropolymer layer to a substrate, a fluoropolymer composition isapplied to a substrate and the fluoropolymer layer is then reacted inthe presence of the organic compound having the hydride function MH tothe substrate. Typically, the organic compound will be present in thefluoropolymer composition and the fluoropolymer composition may alsoinclude a cure composition as described above if an elastomericfluoropolymer layer is desired. Preferably, effective bonding of thefluoropolymer layer is achieved through a participation of the organiccompound in a free radical reaction.

Thus, in an embodiment of the invention, reacting and thereby bondingthe fluoropolymer layer to the substrate is carried out by heating thefluoropolymer layer and the substrate generally in the presence of acompound having one or more groups capable of participating in a freeradical reaction, such as ethylenically unsaturated groups. The compoundhaving such groups may be present in the substrate and/or thefluoropolymer layer. For example, a compound having unsaturated groupsmay be the coagent of a peroxide cure composition described above. Also,in case the substrate comprises a layer of a composition that uponcuring forms a silicone rubber, the composition of this layer willtypically involve compounds having ethylenically unsaturated groups.Generally, reacting the fluoropolymer layer to the substrate will alsoinvolve the use of a free radical generating compound such as forexample a free radical polymerization initiator. Preferably, an organicperoxide is used as a free radical generating compound in particular ifthe fluoropolymer layer includes a peroxide cure system as a curecomposition. However, also other free radical generating compounds canbe used such as for example azo compounds. Bonding of the fluoropolymerto the substrate may be effected by heating the fluoropolymer layerprovided on the substrate to a temperature of 120° C. to 200° C. and for1 to 120 min (preferably 140° C. to 180° C. and for 3 to 60 min.). Theheating may further be carried out while simultaneously applyingpressure.

Reaction of the fluoropolymer layer to the substrate may further becarried out by exposure of the fluoropolymer layer and substrate toactinic radiation, e.g. UV radiation. For example, if a photoinitiatoris included in the substrate and/or fluoropolymer layer, bonding may beeffected through the use of UV radiation. Substrates to which thefluoropolymer layer can be bonded include substrates that have a layercomprising an elastomer. Suitable elastomers include non-fluorine typeof elastomers such as silicone rubbers, acrylonitrile butadiene rubber(NBR), butadiene rubber, chlorinated and chloro-sulfonated polyethylenerubber, chloroprene, copolymers of ethylene and propylene (EPM) rubber,terpolymer of ethylene, propylene, and a diene (EPDM) rubber, ethyleneoxide and chloromethyl oxirane (ECO) rubber, epichlorohydrin-ethyleneoxide-allylglycidylether terpolymer (GECO), polyisobutylene,polyisoprene, polysulfide, polyurethane, blends of polyvinyl chlorideand NBR, styrene butadiene (SBR) rubber, ethylene-acrylate copolymerrubber, and ethylene-vinyl acetate rubber and thermoplastic elastomersderived from ethylene-propylene-diene terpolymer (EPDM) and apolypropylene. Bonding of the fluoropolymer layer to an elastomericlayer of a substrate may involve providing the fluoropolymer layer on alayer comprising a composition that upon curing forms the elastomericlayer. Such is particularly preferred when bonding the fluoropolymerlayer to a silicone rubber. Further substrates include layers offluoropolymers such as for example fluorothermoplastics. Still further,the substrate can be a metal substrate or a plastic substrate includingfor example a non-fluorinated polymer. Examples of non-fluorinatedpolymers include a polyamide, a polyolefin, a polyurethane, a polyester,a polyimide, a polystyrene, a polycarbonate, a polyketone, a polyurea, apolyacrylate, and a polymethylmethacrylate, or a mixture thereof.Polyamides useful as the non-fluorinated polymeric substrate aregenerally commercially available. For example, polyamides such as any ofthe well-known nylons are available from a number of sources.Particularly preferred polyamides are nylon-6, nylon-6,6, nylon-11, andnylon-12. It should be noted that the selection of a particularpolyamide material should be based upon the physical requirements of theparticular application for the multi-layer article. For example, nylon-6and nylon-6,6 offer better heat resistance properties than nylon-11 andnylon-12, whereas nylon-11 and nylon-12 offer better chemical resistanceproperties. In addition, other nylon materials such as nylon-6,12,nylon-6,9, nylon-4, nylon-4,2, nylon-4,6, nylon-7, and nylon-8 can beused, as well as a polymer blend of nylon 6 and polyolefin. Usefulpolyolefin polymers include homopolymers of ethylene, propylene, and thelike, as well as copolymers of these monomers with, for example, acrylicmonomers and other ethylenically unsaturated monomers such as vinylacetate and higher alpha-olefins. Such polymers and copolymers can beprepared by conventional free radical polymerization or catalysis ofsuch ethylenically unsaturated monomers. The degree of crystallinity ofthe polymer can vary. The polymer may, for example, be asemi-crystalline high density polyethylene or can be an elastomericcopolymer of ethylene and propylene. Carboxyl, anhydride, or imidefunctionalities can be incorporated into the polymer by polymerizing orcopolymerizing functional monomers such as acrylic acid or maleicanhydride, or by modifying the polymer after polymerization, e.g., bygrafting, by oxidation, or by forming ionomers. Examples include acidmodified ethylene acrylate copolymers, anhydride modified ethylene vinylacetate copolymers, anhydride modified polyethylene polymers, andanhydride modified polypropylene polymers.

Multi-layer articles having a fluoropolymer layer bonded to a substratein accordance with the invention can be produced by any of the knownmethods for making multi-layer articles. For example, the layers of themulti-layer article can be prepared in the form of thin films or sheetsand then laminated together by application of heat, pressure, orcombinations thereof to form a bonded multi-layer article.Alternatively, each of the layers can be co-extruded to form amulti-layer article. It is also possible to form one or more of theindividual layers by extrusion coating, e.g., using a crosshead die. Theheat and pressure of the method by which the layers are brought together(e.g. extrusion or lamination) can be sufficient to provide adequateadhesion between the layers. It may, however, be desirable to furthertreat the resulting article, for example, with additional heat,pressure, or both, to enhance the bond strength between the layers. Oneway of supplying additional heat when the multi-layer article isprepared by extrusion is by delaying the cooling of the multi-layerarticle at the conclusion of the extrusion process. Alternatively,additional heat energy can be added to the multi-layer article bylaminating or extruding the layers at a temperature higher thannecessary for merely processing the components. As another alternative,the finished multi-layer article can be held at an elevated temperaturefor an extended period of time. For example, the finished article can beplaced in a separate apparatus for elevating the temperature of thearticle such as an oven or heated liquid bath. Combinations of thesemethods can also be used.

Several articles in which a fluoropolymer layer is bonded to a substratecan be made according to the invention. Thus, according to oneembodiment, the article may comprise a fuser member of a plain papercopier system. Such a fuser member may comprise a metal core coveredwith a silicone elastomer that is bonded to a fluoroelastomer fusingsurface layer. Because of the use of the organic hydride compound of theinvention, firm bonding between the fluoroelastomer and silicone layercan be obtained in such a fuser system which may therefore bemanufactured in a more convenient and easy way without the need forintermediate adhesive layers. According to another embodiment, a hosefor use in for example a turbo engine can be made in which a layer offluoroelastomer, generally as an innermost layer, is bonded tonon-fluorine rubber, in particular a silicone rubber.

According to a further embodiment, a fluoropolymer layer comprising athermoplastic fluoropolymer may be bonded to an elastomer. Such layersof thermoplastic fluoropolymer generally represent effective barriersagainst solvents and fuels. Preferably, the thermoplastic fluoropolymeris a fluoropolymer that is halogenated with one or more halogensselected from chlorine, bromine and iodine. Examples of suchthermoplastic fluoropolymers have been described above. By bonding sucha thermoplastic fluoropolymer layer to an elastomer, fuel managementsystems including in particular fuel hoses can be obtained that have ahigh level of impermeability thereby minimizing escape of fuel from afuel system. The thermoplastic fluoropolymer layer can be effectivelybonded to a layer of elastomer that is based on fluoropolymers as wellas a layer of elastomer that is based on non-fluorine containingpolymers. The thermoplastic fluoropolymer layer may also be bonded to anon-fluorinated polymeric substrate.

When bonding the thermoplastic fluoropolymer layer to an elastomer layeror other polymeric substrate, the organic compound having a hydridefunction MH may be included in the fluoropolymer layer having thethermoplastic fluoropolymer and/or in the elastomer layer or polymericsubstrate. In particular, if the elastomer layer is based on anamorphous fluoropolymer, the organic compound may conveniently beincluded in the elastomer layer.

Several layer arrangements of the fuel management system can becontemplated and used. For example, the thermoplastic fluoropolymerlayer may be provided as an innermost layer or outermost layer in abilayer construction. Alternatively, a multilayer arrangement can beused in which the thermoplastic fluoropolymer layer is provided betweentwo layers. For example, a fluoroelastomer layer can be used as aninnermost elastomer layer and the outermost layer can be anon-fluorinated polymer layer including a non-fluorine type ofelastomer. In such a multilayer construction, the thermoplasticfluoropolymer layer can be effectively bonded to both layers as a resultof the presence of the organic compound having a hydride function MH.Preferably, in the latter arrangement, the organic compound would becontained in the thermoplastic fluoropolymer layer.

FIG. 1 and FIG. 2 further illustrate an article according to thisinvention in the form of a tube or hose, for example, a hose suitablefor use as a fuel line or turbo charger compressed air line in anautomobile system. Referring to FIG. 1, there is shown a two-layerarticle 10 that includes a relatively thick outer layer 16 bonded to aninner layer 14. Outer layer 16 can be the non-fluorinated polymer layer,as described above, and is designed to provide article 10 withstructural integrity. Outer layer 16 forms outer surface 18 of the hose.The non-fluorinated polymer can include an elastomer (e.g., siliconerubber, ethylene acrylic rubber, and the like) and a plastic (e.g.,polyamide). Inner layer 14 is a fluoropolymer. Inner layer 14 formsinner surface 12 of the hose. Inner layer 14 imparts chemical andthermal stability to the hose. Inner layer 14 also serves as a barrieror protective layer for outer layer 16 protecting it from solvent, oilor fuel. Because of solvent and permeation resistance of fluoropolymer,inner layer 14 improves the sealing properties preventing leaking at theends of the hose. Some or all of the layers can include an additive torender them electrically conductive. To further enhance structuralintegrity, reinforcing aids such as fibers, mesh, braid, and/or a wirescreen can be incorporated in article 10, e.g., as separate layers or aspart of an existing layer.

Referring to FIG. 2, there is shown a three-layer article 20 thatincludes a relatively thick outer layer 28 bonded to an intermediatelayer 26, which is bonded to a thinner inner layer 24. Outer layer 28can be the non-fluorinated polymer layer, as described above, and isdesigned to provide article 20 with structural integrity. Outer layer 28forms outer surface 30 of the hose. The non-fluorinated polymer caninclude an elastomer (e.g., nitrile rubber, epichlorohydrin rubber, andthe like), which can improve the sealing properties of the article whenthe hose or tube is attached to a rigid connector. Inner layer 24 is afluoroelastomer. Inner layer 24 forms inner surface 22 of the hose.Inner layer 24 imparts chemical and thermal stability to the hose.Because of solvent and permeation resistance of fluoropolymer, innerlayer 24 improves the sealing properties preventing leaking at the ends.Intermediate layer 26 can be a barrier layer, which can decrease vaporor gas penetration through the wall of the hose when the hose iscarrying, for example, a volatile organic solvent. The combination ofinner layer 24 and intermediate layer 26 minimizes the total amount ofpermeation from the hose and connections within a system. Some or all ofthe layers can include an additive to render them electricallyconductive. To further enhance structural integrity, reinforcing aidssuch as fibers, mesh, braid, and/or a wire screen can be incorporated inarticle 20, e.g., as separate layers or as part of an existing layer.

The invention will now be described with reference to the followingexamples without however the intention to limit the invention thereto.All parts are by weight unless indicated otherwise.

EXAMPLES

Abbreviations

-   Fluoroelastomer 1: TFE/HFP/VDF terpolymer, further containing minor    amounts of units derived from 4-bromo-3,3,4,4-tetrafluoro butene.-   Fluoroelastomer 2: bisphenol curable TFE/HFP/VDF terpolymer-   FLS-2650: peroxide curable TFE/HFP/VDF terpolymer, available from    Dyneon-   Fluoroplastic A: Aclar® 33C, a copolymer of CTFE and VDF, available    from Honeywell-   Fluoroplastic B: Aclar® 22C, a copolymer of CTFE and VDF, available    from Honeywell-   TFE: tetrafluoroethylene-   VDF: vinylidene fluoride-   HFP: hexafluoropropylene-   CTFE: chlorotrifluoroethylene-   Ca(OH)₂: calcium hydroxide, Rhenofit CF, available from Rhein    Chemie.-   Carnauba wax: Flora™ 202, available from Int. Wax & Refining Co-   Trigonox™ 101 45B pd: organic peroxide, available from AKZO-   Perkalink™ 301-50: triallyl-isocyanurate, 50% on silicate carrier,    available from Akzo-   TAIC: triallyl-isocyanurate, available from Nippon Kasei-   Varox®t DBPH50: 45% 2,5-dimethyl-2,5-di(t-butylperoxy)-hexan and 5%    di-t-butyl peroxide, available from R. T. Vanderbilt-   CaO: calcium oxide, Rhenofit F, available from Rhein Chemie-   N-774: Semi reinforcing furnace carbon black, available from Degussa-   N-990: carbon black, available from Cancarb-   P-0660: Phenyltris(dimethylsiloxy)silane, available from United    Chemical Technologies-   Elastosil™ 760/70 OH, extrusion grade silicone elastomer, available    from Wacker-   Elastosil™ 401/60 S, silicone elastomer, available from Wacker    Test Methods

Cure and Theological properties of fluoroelastomer compounds wereevaluated using the following test methods:

Cure rheology tests were run on uncured, compounded admixtures using theMoving Die Rheometer (MDR) Model 2000E Monsanto at 177° C. on an 8 gquantity of the admixture in accordance with ASTM D 5289-93a for arotorless rheometer. No preheat, an oscillator frequency of 100 cpm anda 0.5° arc were used. Minimum torque (ML), maximum torque (MH), and thedifference between MH and ML (delta torque), were reported. Alsoreported were Ts2 (the time to a 2 unit rise in torque from ML; Tc50(the time to increase torque above ML by 50% of delta torque), and Tc90(the time to increase torque above ML by 90% of delta torque), all ofwhich were reported in minutes.

Mooney Scorch was measured according to ASTM 1664, Part C (Measuringpre-vulcanisation characteristics), at 121° C. The minimum viscosity(Mmin) was recorded, as well as T3 (time to scorch=Mmin+3 units) and T18(time to cure: Mmin+18 units).

Physical property testing was obtained after 150×150×2 mm³ sheets werepressed and allowed to vulcanise for 7 minutes at 177° C. moldtemperature, followed by post-curing treatment by heating the sheets ina circulating air oven maintained at about 200° C. for 2 hours.

Tensile Strength at Break, Elongation at Break and Stress at 100%Elongation were determined using an Instron™ mechanical tester with a 1kN load cell in accordance with DIN 53504 (S2 die). Test specimen strips(dumbbell) were cut from post-cured sheets. All tests were run at aconstant cross head displacement rate of 200 mm/min in fivefold. Thevalues reported were averages of the five tests. Hardness Shore A (2″),Stress at 100% Elongation, Elongation at Break, and Tensile Strength atBreak were reported in units of Mega Pascals (MPa), %, and MParespectively.

Examples 1 to 3 and comparative examples C-1 to C-3

In examples 1 to 3 and comparative examples C-1 to C-3, curablefluoroelastomer compositions were made on a two-roll mill by mixingcompounds as given in table 1. The compounds are presented in parts byweight per hundred parts by weight of fluoroelastomer (phr) as is customin the rubber industry. Examples 1 to 3 contained 1 phr P-0660 silane,comparative examples C-1 to C-3 were made in the same way, but withoutthe addition of silane. The cure of the resulting mixtures was analysedon 8 g samples of each mixture, using a Monsanto MDR at 177° C. Presscured sheets were prepared by pressing at 177° C. and 6.9 Mpa for 6 min.The press-cured sheets were post-cured in air at about 200° C. for 2hrs. Physical property testing was performed on press-cured andpost-cured sheets; the results are recorded in Table 2. TABLE 1Composition of curable fluoroelastomer composition Compound Ex 1 C-1 Ex2 C-2 Ex 3 C-3 Fluoroelastomer-1 100 100 / / / / Fluoroelastomer-2 / /100 100 / / FLS-2650 / / / / 100 100 Ca(OH)₂ 5 5 5 5 5 5 Trigonox 10145B pd 1 1 1 1 1 1 Perkalink 305-50 6 6 6 6 6 6 CaO 5 5 5 5 5 5 N-774 1515 15 15 15 15 Carnauba wax 0.75 0.75 0.75 0.75 0.75 0.75 Bisphenol AF 11 / / / / Onium* 1.5 1.5 / / / / P-0660 1 / 1 / 1 /Note:onium*: Tributylmethoxypropyl phosphoniumchloride complex

TABLE 2 physical properties of fluoroelastomers Ex 1 C-1 Ex 2 C-2 Ex 3C-3 Monsanto MDR (177° C., test time: 6 min) ML (inch · pounds) 1.1 1.70.8 0.8 1.9 2.0 MH (inch · pounds) 6.0 4.9 15.3 11.4 12.9 11.5 MH-ML(inch · pounds) 4.9 3.2 14.5 10.6 11.0 9.5 Ts2 (min) 2.9 3.3 0.7 1.9 1.31.2 Tc50 (min) 3.4 2.6 1.1 3.0 2.3 1.9 Tc90 (min) 5.4 5.1 3.5 5.0 4.64.5 Mooney Scorch (@ 121° C.) Mmin (inch · pounds) 38 46 56 58 T3 (min)34 >60 47 32 T18 (min) >60 >60 >60 >60 Vulcanisate properties (presscured 7 min @ 177° C., post cured 2 hrs @ 200° C.) Hardness shore A (2″)73 73 72 72 Modulus 100% (Mpa) 7.5 3.4 4.0 4.4 Tensile (Mpa) 18.5 14.013.4 11.8 Elongation (%) 210 328 277 255 Die C tear (kN/m) 21 27 22 21The results in table 2 indicate that the in all cases, fluoroelastomerswith good physical properties were obtained.

In order to evaluate the adhesion between the above fluoroelastomers andvarious silicone rubbers, laminates of fluoroelastomer/silicone rubberwere made. Therefore, sheets were made of the curable fluoroelastomercompositions of about 2 mm thickness and of VMQ compositions of about5-7 mm for making silicone rubbers. From these sheets, strips were cutof about 2.5×7 cm. A narrow strip of PTFE film was inserted between thecurable fluoroelastomer composition and VQM strips, at an edge for about1.5 cm. The PTFE film did not adhere to any of the compositions, and wasused only to create two tabs for insertion into each jaw of an adhesiontesting apparatus. The lamination was accomplished using a hot press at177° C. for 30 min. The superposed strips of curable fluoroelastomercomposition and VMQ compounds, having a total thickness of about 7-9 mmwere pressed in a mold of 6 mm in depth. The high temperature and pressassured vulcanization and the formation of a bond between the twolayers. After cooling to room temperature for 4 hours, the laminatedsheets were cut to a width of about 1.27 to 2.54 cm. The adhesionbetween the two layers was measured according to ASTM D-1876, using aSintech Tester 20 (available from MTS Systems Corporation), with a crosshead speed of 50 mm/min. The results, as given in table 3 are theaverage values of at least three specimens. TABLE 3 adhesion betweenfluoroelastomer/silicone laminates Bond strength (N/mm) Ex 1 C-1 Ex 2C-2 Ex 3 C-3 VMQ A — — >5.7 (RT)   0 (IF) VMQ B — — >4.5 (RT) 0.8 (IF)VMQ C — —   2.6 (IF/RT) — VMQ D 1.1 (IF) 0 (IF) >5.2 (RT) 0.8 (IF)Elastosil 5.2 RT 5.5 RT 401/60S Elastosil 5.1 RT/IF 0.7 IF 760/70 OHNotes:IF = interfacial failure, real indication of bond strengthRT = rubber tear, indicated that the bond was stronger than theelastomer itself. The value recorded was max value.VMQ A-D: VMQ compounds of different composition typically used in makingturbo charger hosesSince the Elastosil ™ samples did not contain curatives, additional 1.5phr Trigonox ™ was used to make the laminates.

The results in table 3 indicate a significant increase in adhesionbetween the fluoroelastomers produced in the presence of the silane andsilicone rubbers produced from a variety of VMQ compositions. Whereasthe comparative examples did not show good adhesion to VMQ compounds(except with Elastosil™ 401/60S), a good to very strong adhesion (rubbertear) was noticed for the fluoroelastomers produced with a silane.

Examples 4 and 5 and Comparative Examples C-4 and C-5

Fluoroelastomer compounds were made using a two roll mill by compounding100 parts FLS-2650, 30 parts N-990, 3 parts calcium hydroxide (availablefrom C. P. Hall), 2.5 parts Varox® DBPH-50, 2.5 parts TAIC and 1 partP-0660. 10 cm×10 cm sheets of about 1.5 mm thickness of curablefluoroelastomer composition were made, adjusting the gap of the rollmill. One sheet of curable fluoroelastomer composition was laminatedagainst a 10 cm×10 cm sheet of fluoroplastic A, having a thickness of0.05 mm (example 4) and another sheet of curable fluoroelastomercomposition was laminated against a 10 cm×10 cm sheet of fluoroplasticB, having a thickness of 0.038 mm (example 5). For comparative examplesC-4 and C-5, curable fluoroelastomer compositions were made as forexamples 4 and 5, except that no P-0660 was added. The comparativecompounds were laminated against fluoroplastic A (comparative exampleC-4) or against fluoroplastic B (comparative example C-5). The laminateswere made using a hot press at 177° C. for 3 minutes. A 15.2 cm×15.2 cmshim stock with 1.25 mm thickness was used to keep the thickness of thelaminate under the heat press. The samples were removed from the pressand allowed to cool to room temperature. The resulting samples were cutinto three 25.4 mm wide strips. Peel or adhesion strength were measuredon the three strips in accordance with ASTM D-1876, using an Instron™Model 1125 tester (available from Instron Corp.), with a cross headspeed of 100 mm/min. In order to facilitate testing of the adhesionbetween the two layers, a 0.05 mm thick polyester was inserted. Theresults, as given in table 4 are the average values of at least threespecimens (only the middle 80% of the sample was taken into account).TABLE 4 adhesion between fluoroelastomers and chlorine containingfluoroplastics Example Chlorine containing Peel strength Nofluoroplastic —SiH co-agent (phr) (N/mm) 4 Fluoroplastic A 1 1.35 IF 5Fluoroplastic B 1 1.45 IF C-4 Fluoroplastic A 0 0.12 IF C-5Fluoroplastic B 0 0.28 IFThe data in table 4 show that substantially improved adhesion betweenfluoroelastomers and chlorine containing fluoroplastics could beobtained if a —SiH co-agent was added to the curable fluoroelastomercomposition.

1. Fluoropolymer composition comprising: (a) a thermoplastic meltprocessible semi-crystalline fluoropolymer comprising chlorine, bromineand/or iodine atoms; and (b) an organic compound comprising a hydridefunction MH, wherein M is selected from Si, Ge, Sn and Pb.
 2. Afluoropolymer according to claim 1 wherein said fluoropolymer is acopolymer of tetrafluoroethylene and/or vinylidene fluoride and one ormore comonomers selected from the group consisting of a chlorinecontaining monomer, ethylene, propylene, hexafluoropropylene,fluorinated vinyl ethers and fluorinated allyl ethers.
 3. Afluoropolymer according to claim 1 wherein said fluoropolymer is acopolymer of tetrafluoroethylene and/or vinylidene fluoride and one ormore comonomers selected from the group consisting ofchlorotrifluoroethylene, vinyl chloride, vinylidene chloride, ethylene,propylene, perfluorinated vinyl ethers and hexafluoropropylene. 4.Fluoropolymer composition comprising: (a) a fluoropolymer; (b) a curecomposition comprising a polyhydroxy compound; and (c) a silazane.
 5. Afluoropolymer according to claim 4 wherein said fluoropolymer is acopolymer of tetrafluoroethylene and/or vinylidene fluoride and one ormore comonomers selected from the group consisting of a chlorinecontaining monomer, ethylene, propylene, hexafluoropropylene,fluorinated vinyl ethers and fluorinated allyl ethers.
 6. Afluoropolymer according to claim 4 wherein said fluoropolymer is acopolymer of tetrafluoroethylene and/or vinylidene fluoride and one ormore comonomers selected from the group consisting ofchlorotrifluoroethylene, vinyl chloride, vinylidene chloride, ethylene,propylene, perfluorinated vinyl ethers and hexafluoropropylene.
 7. Afluoropolymer according to claim 4 wherein said silazane is a disilazanecorresponding to the formula:H_(u)Si(R^(f))_(3-u)—NR^(g)—SiH_(u)(R^(h))_(3-u) wherein u is 1 or 2,R^(f) and R^(h) each independently represents an alkyl group or an arylgroup and R^(g) represents hydrogen, an alkyl group or an aryl group. 8.A fluoropolymer according to claim 7 wherein said disilazane isHSi(CH₃)₂—NH—Si(CH₃)₂H.